From 94454cbb3b62679a137440c3e37ac754b8a31bf6 Mon Sep 17 00:00:00 2001
From: Armon Dadgar <armon.dadgar@gmail.com>
Date: Thu, 6 Aug 2015 17:46:14 -0700
Subject: [PATCH] scheduler: first pass at job deregister

---
 scheduler/scheduler.go     |  3 ++
 scheduler/service_sched.go | 71 +++++++++++++++++++++++++++++++++++++-
 2 files changed, 73 insertions(+), 1 deletion(-)

diff --git a/scheduler/scheduler.go b/scheduler/scheduler.go
index 88f9316f4..165e6d79e 100644
--- a/scheduler/scheduler.go
+++ b/scheduler/scheduler.go
@@ -54,6 +54,9 @@ type State interface {
 	// Nodes returns an iterator over all the nodes.
 	// The type of each result is *structs.Node
 	Nodes() (memdb.ResultIterator, error)
+
+	// AllocsByJob returns the allocations by JobID
+	AllocsByJob(jobID string) ([]*structs.Allocation, error)
 }
 
 // Planner interface is used to submit a task allocation plan.
diff --git a/scheduler/service_sched.go b/scheduler/service_sched.go
index 2aba158d7..b64c14220 100644
--- a/scheduler/service_sched.go
+++ b/scheduler/service_sched.go
@@ -1,6 +1,7 @@
 package scheduler
 
 import (
+	"fmt"
 	"log"
 
 	"github.com/hashicorp/nomad/nomad/structs"
@@ -27,6 +28,74 @@ func NewServiceScheduler(logger *log.Logger, state State, planner Planner) Sched
 }
 
 // Process is used to handle a single evaluation
-func (s *ServiceScheduler) Process(*structs.Evaluation) error {
+func (s *ServiceScheduler) Process(eval *structs.Evaluation) error {
+	// Use the evaluation trigger reason to determine what we need to do
+	switch eval.TriggeredBy {
+	case structs.EvalTriggerJobRegister:
+		return s.handleJobRegister(eval)
+	case structs.EvalTriggerJobDeregister:
+		return s.handleJobDeregister(eval)
+	case structs.EvalTriggerNodeUpdate:
+		return s.handleNodeUpdate(eval)
+	default:
+		return fmt.Errorf("service scheduler cannot handle '%s' evaluation reason",
+			eval.TriggeredBy)
+	}
+}
+
+// handleJobRegister is used to handle a job being registered or updated
+func (s *ServiceScheduler) handleJobRegister(eval *structs.Evaluation) error {
+	// TODO
+	return nil
+}
+
+// handleJobDeregister is used to handle a job being deregistered
+func (s *ServiceScheduler) handleJobDeregister(eval *structs.Evaluation) error {
+START:
+	// Lookup the allocations by JobID
+	allocs, err := s.state.AllocsByJob(eval.JobID)
+	if err != nil {
+		return fmt.Errorf("failed to get allocs for job '%s': %v",
+			eval.JobID, err)
+	}
+
+	// Nothing to do if there is no evictsion
+	if len(allocs) == 0 {
+		return nil
+	}
+
+	// Create a plan to evict these
+	plan := &structs.Plan{
+		EvalID:    eval.ID,
+		Priority:  eval.Priority,
+		NodeEvict: make(map[string][]string),
+	}
+
+	// Add each alloc to be evicted
+	for _, alloc := range allocs {
+		nodeEvict := plan.NodeEvict[alloc.NodeID]
+		nodeEvict = append(nodeEvict, alloc.ID)
+		plan.NodeEvict[alloc.NodeID] = nodeEvict
+	}
+
+	// Submit the plan
+	_, newState, err := s.planner.SubmitPlan(plan)
+	if err != nil {
+		return err
+	}
+
+	// If we got a state refresh, try again to ensure we
+	// are not missing any allocations
+	if newState != nil {
+		s.state = newState
+		goto START
+	}
+	return nil
+}
+
+// handleNodeUPdate is used to handle an update to a node status where
+// there is an existing allocation for this job
+func (s *ServiceScheduler) handleNodeUpdate(eval *structs.Evaluation) error {
+	// TODO
 	return nil
 }